Wondering if anyone uses a winged eyecup on their binos and if so, why or why not and what brand. They intrigue me as a nice way to keep the light out while glassing but I don't see many guys using them. Do they contribute more to eye fatigue or are they maybe just a fad or gimmick? I'm thinking about trying some out on my 10x42 Vipers. Interested to see some thoughts. Thanks!